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laxman · 03-29-2006, 02:34 PM

I totally agree with you on the bad information and misconceptions about TECs. In fact right now I a creating a site that right now has a handful of articles on TEC. I will release the site when I edit my articles and have written up a procedure for my testbench.

Onto what you said about testing, I do not think that undervolting really helps with peltiers because the the Dtmax is also a function of current. So a simple way to model the Dt from water inlet is. Dt= C/W(Qcm)+Dtm(Q/Qcm-1). Both Dtm and Qcm obey Dtm(I)=Dtmo*(I/Imax) and Qcm(I)=Qcmo*(I/Imax). So when you put those into the DT equation you get that DT(I) increases linearly. Meaning you should run peltiers at the max voltage no matter what. Although what throws this model off is the fact that TECs become more effcient as I/Im decreases. I would geuss that your testing would predict that around I/Im=.8->.9 . If we assume that their is some optimal voltage/current to run the peltier at, that voltage and current will change with inlet temp, C/W, Qcm (at max voltage), and Dtm (at max voltage). To say the least that makes things interesting. So I think that the best thing to if would be the optimal voltage, and Qcm for any waterblock with given C/W.

I will help you in any way I can because I am in the same boat as you.

03-29-2006, 02:34 PM	#2
laxman Cooling Neophyte Join Date: Oct 2005 Location: evanston Posts: 41	Re: TEC testing with variable DC PSU I totally agree with you on the bad information and misconceptions about TECs. In fact right now I a creating a site that right now has a handful of articles on TEC. I will release the site when I edit my articles and have written up a procedure for my testbench. Onto what you said about testing, I do not think that undervolting really helps with peltiers because the the Dtmax is also a function of current. So a simple way to model the Dt from water inlet is. Dt= C/W(Qcm)+Dtm(Q/Qcm-1). Both Dtm and Qcm obey Dtm(I)=Dtmo(I/Imax) and Qcm(I)=Qcmo(I/Imax). So when you put those into the DT equation you get that DT(I) increases linearly. Meaning you should run peltiers at the max voltage no matter what. Although what throws this model off is the fact that TECs become more effcient as I/Im decreases. I would geuss that your testing would predict that around I/Im=.8->.9 . If we assume that their is some optimal voltage/current to run the peltier at, that voltage and current will change with inlet temp, C/W, Qcm (at max voltage), and Dtm (at max voltage). To say the least that makes things interesting. So I think that the best thing to if would be the optimal voltage, and Qcm for any waterblock with given C/W. I will help you in any way I can because I am in the same boat as you.